Elliott 403 (WREDAC)

The Elliott 403, also known as WREDAC.
This computer, designed for the Long Range Weapons Research Establishment in
Australia, was a one-off project. It was larger and faster than the 402 by virtue of the
following factors:
(a). The Elliott 403 had a fast, four-word, instruction buffer so that decoding of a following
instruction took place whilst the current instruction was being executed – (a form of
pipelining). It also included a degree of look-ahead at branch instructions.
(b). It had a comparatively large 512-word Immediate-Access store implemented as 12
single-word delay lines (effectively random-access) in the first sub-section, followed by 127
delay lines each of four words.
(c). It had three visible index registers (B-lines), pre-selected by program from four sets
held in the 12 fastest storage locations.